Queen Hedwige had had a serious and legitimate reason for bringing her reception to an abrupt conclusion. A Court ball for the high functionaries and dignities of the Kingdom was to take place that evening.

Furthermore, the Queen was very much exercised over the rumor that the Grand Duchess Alexandra was to be present. This woman, still young and very beautiful, played an important rÔle in the small world of the Palace. It was said by the gossips that she accepted the attentions of Prince Gudulfin, in the hope that some day she might share the throne of Hesse-Weimar with him. For many years she had been a great traveler but in recent times she had spent more and more of her time in Glotzbourg, where she continually met the Prince.

While Juve had experienced no difficulty in being present at the Queen's audience, he found that even Mme. Heberlauf's influence was not sufficient to procure him an invitation to the ball. As a matter of fact, he had no particular wish to appear in the quality of a guest that evening. He had other plans.

At ten o'clock a long line of carriages and automobiles began to arrive in the gardens of the Palace. Innumerable electric lights shone out along the drive-way and from the windows. A few persons had managed to slip past the guards and had stationed themselves near the awning at the main entrance to watch the arrival of the guests. Beneath their fur cloaks, the women wore their very finest gowns and their richest jewelry.

The hall of the chancellory had been transformed into a cloakroom and there the crowd was thickest. In contrast to the brilliantly illuminated left wing of the chÂteau, the octagonal tower showed dark and silent. Hiding behind pillars, keeping close to the walls, a man was making his way slowly toward that tower.

The man was Juve.

From behind a big tree he stood and watched the sky, rubbing his hands with satisfaction.

"This is a night after my own heart," he murmured, "overcast and dark. I should have been very embarrassed had the moon come out."

He felt his pockets.

"Everything I need. My electric lamp and a good, strong, silk ladder."

Then, surveying the tower, he soliloquized:

"A fine monument! Solid and strong. They don't build them like that nowadays."

Juve took a few steps, bent his knees and stretched his arms, tested the suppleness of his body.

"Ah, in spite of my forty-odd years, I'm still pretty fit for ... the work I have to do."

By the aid of the lightning rod, the gutters and the inequalities in the stones, the detective was enabled to climb without much difficulty to the first floor.

There he paused to take breath and to examine the shutters of a window.

"Can't get in that way," he muttered, "they're bolted inside. I'll have to climb higher."

The same condition met him on the second floor, but when he had finally reached the roof, he espied a large chimney which promised a method of ingress to the apartment below. The descent was anything but easy, and Juve, in spite of his great strength and agility, was used up by the time he had reached the bottom. His clothes were torn and he was covered with the greasy soot he had accumulated on his journey. By dint of brushing and scraping, he succeeded in cleaning off the worst of it, and then looked round to take his bearings.

He had landed in the large waiting-room which adjoined the royal apartments.

The distant sound of dance music came to his ears and the atmosphere of the place was cold and damp.

"He doesn't often come here, I'll bet," thought Juve.

A door led him directly into the King's bathroom, and Juve paused to admire the famous bath of solid silver which the municipality had presented to the King upon one of his birthdays.

"I've a good mind to take a tub," he muttered. "Maybe I shall find His Majesty locked in his bedroom, and I'm hardly a fit sight to appear before him."

The detective now felt some cause for anxiety.

There were two alternatives to consider. Either the King was absent, and in that case Juve's business would be to discover the hiding place of the diamond and clear up the question whether the King had taken it with him, or, if he had been sequestered, to discover his prison.

Clutching the butt of his Browning revolver in his pocket, the detective opened the door to the King's bedroom and entered.

A thick carpet deadened the sound of his footsteps. After listening for a few moments he relit his pocket lamp and flashed it round the room.

In the centre stood an immense bed of oak designed in Renaissance style, the posts of which reached to the ceiling. Three steps led up to it. Juve noticed that it had not been disturbed. The sheets and pillows were all in order. There was nothing, however, to indicate that the King had been absent for any length of time.

Upon one point he was certain: The King was not concealed anywhere about the room, and the more he thought of the Burgomaster's suspicion, the less he thought it plausible. But if the King had not been sequestered, it was quite possible that he might be purposely hiding after his unfortunate adventure of the Rue de Monceau. Therefore, Juve decided to pursue his search through the other rooms.

But first he began mechanically to tap the wood-work, looking behind the pictures for the hiding place of the famous diamond. In his time he had seen so many secret drawers, double-seated chairs, and numerous contrivances of a similar sort, that it would be a cunning hand that could baffle his perspicacity and experience.

He had just examined a chair when suddenly he stopped in his work and waited, listening. The sound of footsteps some distance off struck his ear. Without a moment's hesitation he put out his light and darted behind the curtains. It was a good position to take up for he could see without being seen.

The footsteps drew near, the door opened and a light from an electric lantern similar to the one Juve had used, was thrown into the room.

The individual advanced to the bed, all unaware of Juve's presence. Stooping down, he began feeling the foot of one of the bedposts, which at this point formed a bulge. In an instant the wood parted and disclosed a hollow in which lay a jewel case. The jewel case contained the famous red diamond.

Juve's heart began to thump as he watched the man open the case and take out the diamond. Its facets reflected the light, multiplying the gleams and bringing into relief the features of the robber.

Then it was that the detective uttered a great cry, a cry of agony, of anger and of triumph. The man was wrapped in a great cloak, his face hidden by a black mask, but there was no mistaking his identity. It was FantÔmas.

Juve's cry called forth another, ferocious and menacing, and then in a moment the room was plunged into darkness and the two men sprang at one another. Two revolver shots rang out. The dancers heard them in the ballroom and stopped dancing. The musicians heard them and ceased playing.

At once a stampede ensued.

Two officers of the guard rushed to the door leading to the King's apartments, and flung it wide open. One of them turned on the electric light and, followed by the frightened guests, entered the King's bedchamber.

At the foot of the bed, struggling in a long cloak, a man with his hands over his face lay moaning. By his side was a smoking revolver, and on the ground the empty jewel case.

"Arrest him!" somebody cried.

In a moment a number of hands had seized and bound him. It was noticed that his eyelids were fearfully swollen and the eyes bloodshot.

What had happened!

The struggle between Juve and the monster had scarcely lasted a second.

The detective had fired point blank at the black mask and as his finger pressed the trigger he had felt the whistle of a bullet past his ear.

Then a door had opened slightly, letting in a thin shaft of light. To his amazement, FantÔmas no longer stood before him, but an officer in the uniform of the Queen's lancers.

Juve was not taken in by this quick change, and was on the point of firing again when suddenly his eyes were filled with a blinding powder, burning and blistering the pupils. He had been blinded by pepper. Instinctively he put his hands to his face, and in that moment he felt himself enveloped in the long cloak in which FantÔmas had entangled him. Falling to the ground in agony he then heard the cry:

"Help! Help!"

By the sudden and growing noise, he realized that the crowd was drawing near. When he had struggled to a sitting posture, he found himself a prisoner.

The sudden change from darkness to bright light increased the pain in his eyes, but with a superhuman effort he was enabled to pick out the superb uniform of the false lancer. Pointing to him, he cried:

"Arrest him, why don't you arrest him!"

Brutally, he was told to keep quiet.

The noise of the theft spread rapidly and the greatest confusion reigned in the Palace. Many of the women fainted. Finally M. Heberlauf arrived. He appeared immensely important, and confided to a group his opinion of the affair, adding this restriction:

"At any rate, that is what my wife believes."

Mme. Heberlauf had, in fact, after an interview with one of the officers, announced it as her opinion that the thief so providentially arrested was no other than the world-famous and unseizable FantÔmas.

And then a queer thing happened. When the Grand Duchess Alexandra heard this sinister name spoken, when she knew that FantÔmas had been arrested, she staggered as though struck to the heart and fell fainting into the arms of her friends.

"FantÔmas!" she murmured, "FantÔmas arrested! Can it be possible?"

Juve was taken away tightly bound. He seemed indifferent to the clamor of the crowd and constantly looked from side to side as though searching for something or somebody. Suddenly, as he passed the group surrounding the Grand Duchess Alexandra, he made a violent effort and dragged his captors close enough to enable him to see the fainting woman's features. One look was enough, and then without further resistance he allowed himself to be marched away. He had found out what he wanted to know; he had recognized in the Grand Duchess the mistress of FantÔmas, the accomplice of his most dreadful crimes. He had seen Lady Beltham!